Field of the Disclosure
The present disclosure relates to a voice coil motor (VCM).
Discussion of the Related Art
Recently, a mobile phone mounted with a super-small high resolution digital camera has been developed. The super-small digital camera mounted on the mobile phone includes an image sensor changing an outside light to an image and a lens opposite to the image sensor.
The conventional super-small digital camera is fixedly mounted with the lens and the image sensor to have a trouble in obtaining a high quality image due to difficulty in adjusting a distance between the image sensor and the lens.
Recently, a lens driving device such as a voice coil motor has been developed to adjust a distance between a lens and an image sensor. The voice coil motor generally includes a bobbin secured with a lens, a coil block wound on a periphery of the bobbin, a magnet opposite to the coil block, a yoke securing the magnet, and a leaf spring elastically supporting the vertically-moving bobbin.
The magnet, one of the essential components of the conventional voice coil motor, or, is secured to an inner lateral surface of the yoke using an adhesive. However, in a case the magnet is secured to the inner lateral surface of the yoke using an adhesive, the magnet is separated from the yoke by a strong shock or a vibration applied to the yoke, and if the magnet is separated from the yoke, the bobbin is generated with a problem of defective driving.
Another problem encountered by the conventional voice coil motor is that a yoke is needed to secure a yoke the magnet opposite to the bobbin whereby the number of parts and assembly processes is increased.
Still another problem is that an aperture of the lens mounted on the bobbin cannot be increased due to an area occupied by the bobbin and the magnet.